Android：为什么没有显示最近和自定义搜索建议？

Question

我试图在我的应用中使用搜索建议。它应该显示来自网络的最近搜索和自定义搜索建议。但是以下代码不起作用。我无法弄清问题是什么。有人可以帮忙吗？

MainActivity：

public class MainActivity extends AppCompatActivity {
    public SearchView searchView;
    ListView list;
    ArrayList<String> li;
    String url;
    String key, value;
    SearchRecentSuggestions sugg;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        list = (ListView) findViewById(R.id.listView1);

        Intent intent = getIntent();
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        // handleIntent(intent);
        if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
            String query = intent.getStringExtra(SearchManager.QUERY);
            sugg = new SearchRecentSuggestions(
                    this, SampleRecentSuggestionsProvider.AUTHORITY,
                    SampleRecentSuggestionsProvider.MODE);
            sugg.saveRecentQuery(query, null);
        }

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        super.onCreateOptionsMenu(menu);
        getMenuInflater().inflate(R.menu.main, menu);

        SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
        searchView = (SearchView) menu.findItem(R.id.action_search)
                .getActionView();
        searchView.setSearchableInfo(searchManager
                .getSearchableInfo(getComponentName()));
        searchView.setIconifiedByDefault(true);
        searchView.setFocusable(true);
        searchView.setIconified(false);
        searchView.requestFocusFromTouch();
        return true;
    }
}

SearchRecentSuggestionsProvider：

public class SampleRecentSuggestionsProvider extends
        SearchRecentSuggestionsProvider {
    public static final String AUTHORITY = "com.example.SampleRecentSuggestionsProvider";
    ArrayList<String> li;

    public static final int MODE = DATABASE_MODE_QUERIES;

    final List<String> suggestions = new ArrayList<>();


    String[] columns = { BaseColumns._ID,
          SearchManager.SUGGEST_COLUMN_TEXT_1,
          SearchManager.SUGGEST_COLUMN_INTENT_DATA };

    MatrixCursor cursor = new MatrixCursor(columns);

    public SampleRecentSuggestionsProvider() {
        setupSuggestions(AUTHORITY, MODE);

    }

    @Override
    public int delete(Uri arg0, String arg1, String[] arg2) {
        return 0;
    }

    @Override
    public String getType(Uri uri) {

        return null;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        return null;
    }

    @Override
    public boolean onCreate() {
        return false;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
            String[] selectionArgs, String sortOrder) {

        li = new ArrayList<String>();
        JsonObjectRequest jobjRequest = new JsonObjectRequest(url
                        + selectionArgs[0].trim(),
                new Response.Listener<JSONObject>() {
                    @Override
                    public void onResponse(JSONObject response) {

                        try {
                            JSONArray sugg = response.getJSONArray(array);

                            Log.e("USER", "" + sugg);

                            for (int i = 0; i < sugg.length(); i++) {
                                li.add(sugg.getString(i));
                            }

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }

                        suggestions.clear();
                        suggestions.addAll(li);

                        Log.e("Suggestions ", "" + suggestions);

                        for (int i = 0; i < li.size(); i++) {
                            String[] tmp = { Integer.toString(i), li.get(i),li.get(i) };
                            cursor.addRow(tmp);
                        }

                    }
                }, new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(getContext(), error.getMessage(),Toast.LENGTH_LONG).show();
                    }
                });

        RequestQueue requestQueue = Volley.newRequestQueue(getContext());
        requestQueue.add(jobjRequest);
        Cursor recentCursor = super.query(uri, projection, selection, selectionArgs, sortOrder);
        MatrixCursor returnMatrix = cursor;
        cursor = new MatrixCursor(columns);
        Cursor[] cursors = new Cursor[] { recentCursor, returnMatrix };
        return new MergeCursor(cursors);
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection,
            String[] selectionArgs) {
        return 0;
    }
}

Searchable.xml：

 <?xml version="1.0" encoding="utf-8"?>
<searchable xmlns:android="http://schemas.android.com/apk/res/android"
    android:label="@string/app_name"
    android:hint="@string/search_hint"
    android:searchSuggestAuthority="com.example.SampleRecentSuggestionsProvider"
    android:searchSuggestSelection=" ?" >
</searchable>

清单：

<category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
        <intent-filter>
            <action android:name="android.intent.action.SEARCH" />
        </intent-filter>

    <meta-data
        android:name="android.app.searchable"
        android:resource="@xml/searchable" />
</activity>

    <provider
        android:name=".SampleRecentSuggestionsProvider"
        android:authorities="com.example.SampleRecentSuggestionsProvider"
        android:enabled="true" />